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I have a external hard disk and protected a partition on it with Bitlocker To Go. I printed the recovery code but I lost it. I can't remember the user PIN either. If I could only know the first characters of the PIN, I'm sure I would remember the rest. I work on a Windows 7 x64 system. The TPM was not enabled when I activated Bitlocker. I only used a recovery key and a user PIN with more than seven characters.

My question is: Does a (brute force) software exist that can find (the first) characters of the PIN (user password), or is the information on it lost?

I know the recovery password can't be brute-forced in a million years. I only hope it's possible to find a few digits of the pin so I'll remember the rest of it.

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It's not possible to find arbitrary digits of the pin. It's an all-or-nothing deal.

Assuming a numeric pin, there are 10,000,000 possible combinations. Depending on the implementation of the key derivation algorithm, it may take up to ~1s per attempt - that's roughly 58 days before you have a 50% chance of hitting the correct key, with 116 days (almost 4 months) being the worst-case time.

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Add to that I believe that once you get above 5 incorrect attempts it increases the time between tries to a minute or more. Got a few decades? – GdD Sep 26 '12 at 15:46
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...and if I'm not mistaken, some implementations can brick the device after N attempts. – Eric Fleischman Sep 26 '12 at 16:23
@EricFleischman, that's true for entering the password to unlock, I'm not sure you can configure the same options for the recovery pin. – GdD Sep 26 '12 at 16:36
Ah, I'm sorry, I thought we were talking about the password. I misread. – Eric Fleischman Sep 26 '12 at 16:52

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